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Abstract:

Described herein are substantially linear copolymeric compositions having
at least two azide groups and at least two non-activated acetylene
groups. The azide groups and the non-activated acetylene groups are
reacted to cure the substantially linear copolymer composition. Also,
described are methods of making and using such substantially linear
copolymeric compositions.

15. The composition of claim 13 further comprising a compound, wherein
the compound comprises a functional entity and at least one pendant
non-activated acetylene group or azide group.

16. The composition of claim 13, wherein the composition is at least one
of an adhesive or a coating.

17. An article comprising the composition as described claim 13, wherein
the article is a filled polymer, a reinforced composite, or a structural
article.

18. An article comprising: a. a substrate; and b. a polymer layer
comprising: i) a substantially linear, randomly copolymerized polymer,
ii) at least two azide groups, and iii) at least two non-activated
acetylene group, wherein at least one ii) or iii) is attached to the
substantially linear, randomly copolymerized polymer; and wherein the
polymer layer is cross-linked by reacting the ii) and iii).

19. The article of claim 18 wherein the article is an adhesive coated
sheet material.

20. The article of claim 18 wherein the substrate is film.

Description:

TECHNICAL FIELD

[0001] A novel cure system is described using azide and non-activated
acetylene. Polymeric compositions using this cure system are described as
well as the methods of making and using such polymeric compositions. For
example, this cure system may be used in pressure sensitive adhesive
applications.

BACKGROUND

[0002] Acrylate pressure sensitive adhesives are well-known in the art.
Ulrich (U.S. Pat. No. RE 24,906) describes alkyl acrylate copolymers,
which comprise a major amount of C4 to C14 alkyl esters of acrylic acid
monomers and a minor portion of a copolymerizable polar monomer such as
acrylic acid. Such adhesives are widely popular due to their
availability, their low cost, and their ability to provide the requisite
fourfold balance of adhesion, cohesion, stretchiness, and elasticity
known to be required for effective pressure sensitive adhesives.

[0003] The advantage of acrylic polymers as viscoelastic bases for
pressure sensitive adhesives are well known in the art. U.S. Pat. No. RE
24,906 (Ulrich) cites many examples of these products. Initially, such
compositions were made via solution polymerization. However, such methods
of polymerization involved the use of large amounts of organic solvents,
which may be undesirable for economic reasons.

[0004] The acrylic polymers must be in a form such that they can be coated
or applied in a manner that is desirable, for example, a smooth and level
coating on a film to make a tape. In this tailored structure, the polymer
may lack properties for the end use such as cohesive strength, tensile
strength, or modulus. To attain end use properties, cross-linking or
curing is contemplated to decrease chain slippage when a stress is
applied.

[0005] Current strategies to cross-link polymers in coating applications
involve high energy processes such as e-beam, gamma, and ultraviolet
irradiation. These processes are limited in depth of cross-linking when
applied to thick layers of polymer, and use a high amount of energy.

[0006] Many of the chemical routes to cross-link polymers involve cures
including polyisocyanates and polyaziridines. These cures have short pot
lives, making it difficult to achieve a uniform coat before the
cross-linking reaction occurs.

[0007] Recently, it has become known to form a 1,3-cyclo-addition of
azides with terminal acetylene (also known as a 3+2 cycloaddition) using
a copper catalyst at room temperature in what is known as a "click
reaction". Katritzky, et al., in J. Poly. Sci.: Part A, v. 46, 238-256
(2008), describe the preparation and characterization of end-capped
azides and alkynes, wherein the azides were combined in 1,3-dipolar
cycloaddition reactions to form triazole linked polymers.

[0008] However, U.S. Pat. No. 5,681,904 (Manzara), has taught away from
cross-linking azides with activated acetylene (i.e., acetylene linked
directly to a carbonyl) because such reactions are relatively fast and
would lead to a short pot life.

SUMMARY

[0009] There is a desire to identify a chemical route to cross-link
polymers that limits energy usage, allows for long pot lives, and
provides sufficient cross-linking.

[0010] As disclosed herein, the present disclosure provides the tailoring
of polymeric performance in applications such as pressure sensitive
adhesives, films, and coatings. Further, the cohesive strength, tensile,
modulus, and adhesion performance also may be improved.

[0011] Briefly, in one embodiment, the present disclosure provides a
composition comprising a substantially linear copolymer having at least
two randomly distributed interpolymerized non-activated acetylene
cure-site monomers and a curing agent, wherein the curing agent comprises
at least two azide groups.

[0012] In another embodiment, a method is provided comprising providing a
substantially linear copolymer having at least two randomly distributed
interpolymerized non-activated acetylene cure-site monomers and
cross-linking with a curing agent, wherein the curing agent comprises at
least two azide groups.

[0013] In yet another embodiment, an article is provided comprising a
composition comprising a substantially linear copolymer having at least
two randomly distributed interpolymerized non-activated acetylene
cure-site monomers and a curing agent, wherein the curing agent comprises
at least two azide groups.

[0014] In yet another embodiment, a composition is provided comprising a
substantially linear copolymer having at least two randomly distributed
interpolymerized azide cure-site monomers and a curing agent, wherein the
curing agent comprises at least two non-activated acetylene groups.

[0015] In another embodiment, a method is provided comprising providing a
composition comprising a substantially linear copolymer having at least
two randomly distributed interpolymerized azide cure-site monomers and
cross-linking with a curing agent, wherein the curing agent comprises at
least two non-activated acetylene groups.

[0016] In yet another embodiment, a composition is provided comprising a
substantially linear copolymer having, on the polymer backbone, at least
one randomly distributed interpolymerized azide cure-site monomer and at
least one randomly distributed interpolymerized non-activated acetylene
cure-site monomer.

[0017] In another embodiment, a method is provided comprising providing a
substantially linear copolymer having, on the polymer backbone, at least
one randomly distributed interpolymerized azide cure-site monomer and at
least one randomly distributed interpolymerized acetylene cure-site
monomer and cross-linking.

[0018] In yet another embodiment, an article is provided comprising a
substrate and a polymer layer wherein the polymer layer comprises: i) a
substantially linear, randomly copolymerized polymer, ii) at least two
azide groups, and iii) at least two non-activated acetylene groups,
wherein at least one of ii) or iii) is bonded to the substantially
randomly copolymerized polymer; and wherein the polymer layer is
cross-linked by reacting the at least two azide groups and the at least
two non-activated acetylene groups.

[0019] The above summary is not intended to describe each embodiment. The
details of one or more embodiments of the invention are also set forth in
the description below. Other features, objects, and advantages will be
apparent from the description and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

[0020] FIG. 1 is a graph of G' versus time for Comparative Example 1 and
Examples 1-3.

[0021]FIG. 2 is a graph of G' versus time for Comparative Example 1 and
Examples 4-7.

[0022] FIG. 3 is a graph of log G' versus time for Comparative Example 2
and Examples 8-10.

[0023] FIG. 4 is a graph of log G' versus time for Comparative Example 3
and Examples 11-12.

DETAILED DESCRIPTION

[0024] As used herein, the term

[0025] "a", "an", and "the" are used interchangeably and mean one or more;

[0026] "and/or" is used to indicate one or both stated cases may occur,
for example A and/or B includes, (A and B) and (A or B);

[0027] "cross-linking" refers to connecting two pre-formed polymer chains
using chemical bonds or chemical groups in order to increase the modulus
of the material;

[0028] "cure-site" refers to functional groups, which may be pendant from
any monomer unit and may participate in cross-linking;

[0029] "end-capped" refers to polymers that have been made or modified by
positioning a specific group at the end(s) of the polymer chain, which
can then be used for subsequent reactions to increase chain length;

[0030] "interpolymerized" refers to monomers that are polymerized together
to form a polymer backbone; and

[0031] "(meth)acrylate" refers to compounds containing either an acrylate
(CH2═CHCO.sup.-) or a methacrylate
(CH2═CCH3CO.sup.-) structure or combinations thereof.

[0032] Also herein, recitation of ranges by endpoints includes all numbers
subsumed within that range (e.g., 1 to 10 includes 1.4, 1.9, 2.33, 5.75,
9.98, etc.).

[0033] Also herein, recitation of integer ranges by endpoints includes all
integers subsumed within that range (e.g., 1 to 10 includes 1, 2, 3, 4,
5, etc.).

[0034] Also herein, recitation of "at least two" includes all numbers of
two and greater (e.g., at least 4, at least 6, at least 8, at least 10,
at least 25, at least 50, at least 100, etc.).

[0035] Also herein, recitation of "at least one" includes all numbers of
one and greater (e.g., at least 2, at least 4, at least 6, at least 8, at
least 10, at least 25, at least 50, at least 100, etc.).

[0036] This disclosure provides an azide-acetylene cure system for
polymers. Although not wanting to be bound by theory, it is believed that
the non-activated acetylene and the azide react in a 3+2 cycloaddition to
form a 1,2,3-triazole.

[0037] As disclosed herein, an azide-acetylene cure system refers to the
use of azide groups and non-activated acetylene groups to cross-link
polymer chains. At least three embodiments of the azide-acetylene cure
system are contemplated in this disclosure. In one embodiment, the
substantially linear copolymer comprises randomly distributed
interpolymerized monomers comprising a non-activated acetylene cure-site
and the curing agent comprises at least two azide groups. In another
embodiment, the substantially linear copolymer comprises randomly
distributed interpolymerized monomers comprising an azide cure-site and
the curing agent comprises at least two non-activated acetylene groups.
In another embodiment, a substantially linear copolymer comprising, on
the substantially linear copolymer backbone, at least one randomly
distributed interpolymerized azide cure-site monomer and at least one
randomly distributed interpolymerized acetylene cure-site monomer.

[0038] A non-activated acetylene group, as disclosed herein, means that
the acetylene in the substantially linear copolymer or the curing agent
is connected via an aliphatic carbon group, --CR2--, where R is
independently H or a non-interfering organic group, i.e., R does not
sterically or electronically hinder the acetylene group from cycloadding
to the azide. R may be hydrogen, deuterium, a small alkyl group, and so
forth. The non-activated acetylene group does not have a carbonyl group
linked directly to the carbon atom of the acetylene. In other words, the
non-activated acetylene is not --C(═O)--C≡C--.

[0039] The polymers contemplated in this disclosure are substantially
linear copolymers. Substantially linear means that the copolymer is a
linear polymer that may comprise light to moderate branching, but that
the copolymer is not a highly-branched (e.g., dendritic) polymer.
Quantitatively, substantially linear refers to less than ten branches for
every 100 monomer units in the polymer backbone, less than five branches
for every 100 monomer units in the polymer backbone, or even one branch
for every 100 monomer units in the polymer backbone. The substantially
linear copolymers of this disclosure may be randomly (e.g., free
radically) polymerized. By copolymer is meant herein a polymer comprising
at least two different interpolymerized monomers (i.e., the monomers not
having the same chemical structure) and include: terpolymers (comprising
three different monomers), tetrapolymers (comprising four different
monomers), etc.

[0040] In some embodiments, the substantially linear copolymer is
hydrophilic. In some embodiments, the substantially linear copolymer is
hydrophobic. In some embodiments, the substantially linear copolymer has
a number average molecular weight (Mn) of at least 50,000 dalton, at
least 100,000 dalton, at least 300,000 dalton, at least 500,000 dalton,
at least 750,000 dalton, at least 1,000,000 dalton, or even at least
1,500,000 dalton.

[0043] (Meth)acrylate amide monomers may include: acrylamide with or
without additional organic groups instead of hydrogen on the nitrogen
atom, and methacrylamide with or without additional organic groups
instead of hydrogen on the nitrogen atom. The organic groups may include:
alkyl, aryl, alkaryl, hydroxyl, amine, ammonium, ether, ester, urethane,
or other groups.

[0044] (Meth)acrylic acid monomers may include acrylic acid or methacrylic
acid or their salts.

[0045] The (meth)acrylate monomer may be present in an amount of 80 to 99
parts by weight based on 100 parts total monomer content used to prepare
the substantially linear copolymer. Preferably (meth)acrylate monomer may
be present in an amount of 90 to 95 parts by weight based on 100 parts
total monomer content. (Meth)acrylates may make up most of the
substantially linear copolymer backbone and are also the comonomers,
which are used to incorporate the azide cure-site or non-activated
acetylene cure-sites into the substantially linear copolymer.

[0046] In one embodiment of the azide-acetylene cure system, a curing
agent comprising at least two azide groups is added to a substantially
linear polymer comprising at least two randomly distributed non-activated
acetylene groups.

[0047] The azide compound used as the curing agent comprises at least two
azide groups (i.e., at least two N3 groups). The azide compound used
as the curing agent may be of the formula: G(N3)m where m is an
integer from 2 to about 10 and G is a m-valent organic group, where at
least two of the azide (N3) groups are connected via aliphatic
carbon atoms, where G may contain other non-interfering organic groups
such as alkyl, aryl, alkaryl, hydroxyl, halogens, amine, ammonium, ether,
ester, urethane, or other groups that do not interfere with the desired
reaction. The azide compound used as the curing agent may be of low
molecular weight such as compounds having a molecular weight of less than
1,000, oligomers between 1,000 and 20,000 molecular weight, or polymers
with greater than 20,000 molecular weight.

[0048] Examples of an azide compound used as the curing agent include, but
are not limited to:
CH3CH2C(OCH2CH--OHCH2N3)3,
N3CH2CH2O[CH2CH(CH2N3)O]6CH3,
CH3CH2C[CH2(OCH2CH(CH2N3))2OCOCH3-
]3, CH3CH2C[CH2(OCH2CH(CH2N3))2OH]-
3, N3CH2CH2OCH2CH(OH)CH2N3,
poly-urethane of N3CH2CH2OH with polyisocyanate,
tris-2-azido-ethyl trimesoate, hexane-1,6-bis-azidoethyl-urethane,
polyoxyethylene bis(azide), bis-azide dye, 1,8-diazidooctane, and
combinations thereof. Other polyazide compounds are contemplated in this
disclosure including those which contain more than 46% by weight
nitrogen.

[0049] In one embodiment, the azide compound used as the curing agent is
stable (i.e., it does not lose molecular nitrogen to form a nitrene)
under the cross-linking conditions (e.g., temperature and time) needed to
change the mechanical properties of the polymer.

[0050] The non-activated acetylene group of the interpolymerized
non-activated acetylene cure-site monomer may be incorporated into the
substantially linear copolymer during polymerization by use of a
non-activated acetylene-containing monomer or by a post-polymerization
reaction step. However, other methods of introduction are also
contemplated by this disclosure. Examples of a non-activated
acetylene-containing monomer include, but are not limited to:
propargyl(meth)acrylate, and the propargyl ether of 4-vinyl phenol.
Post-polymerization reactions are described below.

[0051] The substantially linear copolymer must contain a sufficient
quantity of non-activated acetylene groups that can act as cure-sites for
cross-linking. The amount of non-activated acetylene-containing
cure-sites in a side chain position of the substantially linear copolymer
generally is from about 0.01 to about 5 mole percent or even from 0.05 to
3 mole percent relative to the substantially linear copolymer. However,
not all of the non-activated acetylene cure-sites need to be reacted as
long as the desired end properties are achieved.

[0053] In another embodiment of the azide-acetylene cure system, a curing
agent comprising at least two non-activated acetylene groups is added to
a substantially linear polymer comprising at least two randomly
distributed azide groups.

[0054] The non-activated acetylene compound used as the curing agent
comprises at least two non-activated acetylene groups. The non-activated
acetylene compound used as the curing agent may contain other
non-interfering organic groups (such as alkyl, aryl, or alkaryl, which
may contain hydroxyl, halogen, ionic, amine, ammonium, ether, urethane,
or other groups that do not interfere with the desired reaction). The
non-activated acetylene compound used as the curing agent may be of low
molecular weight such as compounds having a molecular weight of less than
1,000, oligomers between 1,000 and 20,000 molecular weight or polymers
with greater than 20,000 molecular weight.

[0056] The azide group of the interpolymerized azide cure-site monomer may
be of the formula: P--R--N3 where R is an organic group (such as
alkyl or aralkyl, which may contain, hydroxyl, amine, ammonium, ether,
ester, urethane, or other groups that do not interfere with the desired
cross-linking reaction), which connects the azide group to the
substantially linear copolymer backbone and P is the substantially linear
copolymer backbone, where the substantially linear copolymer backbone may
carry other non-interfering organic groups (such as alkyl, aryl, or
alkaryl, which may contain ionic, halogen, hydroxyl, amine, ammonium,
ether, ester, urethane, or other groups that do not interfere with the
desired cross-linking reaction).

[0057] The azide group of the interpolymerized azide cure-site monomer may
be incorporated into the substantially linear copolymer during
polymerization by use of an azide-containing monomer or by a
post-polymerization reaction step. However, other methods of introduction
are also contemplated by this disclosure.

[0058] Examples of an azide-containing monomer include, but are not
limited to: azidoethyl methacrylate, azidopropyl methacrylate or other
free-radical polymerizable monomers, wherein the polymerizable bond does
not react with the azide group during monomer synthesis or
polymerization. Post-polymerization reactions are described below.

[0059] Post-polymerization reactions may be used to incorporate or unblock
the active cure-sites, as long as the cure-site functional group (either
the azide or the non-activated acetylene) does not interfere with the
post-polymerization reaction. The azide group or non-activated acetylene
group, or a compound containing such group, may be attached to the
substantially linear copolymer via direct esterification,
transesterification, transamidation of esters, direct amidation, urethane
formation, epoxy ring opening, aziridine ring opening, salt formation,
nucleophilic displacement, amine quaternization, and other methods known
to those skilled in the art. An example of a post-polymerization reaction
involving an unblocking technique is the use of
trimethylsilylpropargylmethacrylate or trimethylsilylpropargylacrylate
where the trimethyl silyl group is removed after polymerization. Another
example of a post-polymerization reaction includes the reaction of a
compound comprising the cure-site functional group and an aziridine
group. This compound can react with the carboxylic acid groups on the
(meth)acrylate copolymer to link the cure-site functional group to the
substantially linear copolymer backbone. Similarly, silanes may also be
used in post-polymerization reactions to link the cure-site functional
group to the substantially linear copolymer backbone. Examples of such
silanes include, but are not limited to: 3-azidopropryl triethoxysilane,
silanesulfonyl azide, and 6-azidosulfonyl hexyl triethoxysilane.

[0060] The substantially linear copolymer must contain a sufficient
quantity of azide groups that can act as cure-sites for cross-linking.
The amount of azide-containing cure-sites in a side chain position of the
substantially linear copolymer generally is from about 0.01 to about 5
mole percent or even from 0.05 to 3 mole percent relative to the
substantially linear copolymer. However, not all of the azide cure-sites
need to be reacted, as long as the desired end properties are achieved.

[0062] In another embodiment of the azide-acetylene cure system, the
substantially linear copolymer comprises at least one randomly
distributed interpolymerized azide cure-site monomer and at least one
randomly distributed interpolymerized non-activated acetylene cure-site
monomer. The interpolymerized azide cure-site monomers and the
interpolymerized non-activated acetylene cure-site monomers include those
as described above.

[0063] An example of such an embodiment is copolymerizing azidoethyl
methacrylate and propargyl methacrylate with other (meth)acrylate
monomers. Other free-radically polymerizable monomers may also be used as
long as they do not react with the azide group or the non-activated
acetylene group under the polymerization conditions. The incorporation of
both the azide and the non-activated acetylene into the same
substantially linear copolymer enables the cross-linking of the
substantially linear copolymer without the need for additional curing
agents. Such a strategy eliminates errors that might be made in the
subsequent formulation of the substantially linear copolymer due to
mischarging of the low levels of curing agent. With this strategy there
is less of a possibility of curing agent loss due to thermal vaporization
and, when applying the composition to a substrate, there is less of a
possibility that the curing agent will diffuse into the substrate or
adjacent layers before and during cross-linking

[0064] In yet a further embodiment of this disclosure, using similar
chemistry as described above, a compound comprising a functional entity
and at least one pendant non-activated acetylene group or azide group may
be added to the disclosures disclosed herein. In another embodiment, the
curing agent may be a compound comprising a functional entity and at
least two pendant non-activated acetylene groups or azide groups.

[0065] The functional entities may include a chemical group, which
interacts with the environment in a useful way. For example, the
functional entity may: absorb light (such as a dye), modify light (such
as a polarizer, photoinitiator, etc.), act as a photostabilizer, act as
an antioxidant, provide a self-healing property, act as a free-radical
initiator, lower the surface energy, act as an identifiable marker,
provide hydrophilicity or hydrophobicity, absorb and/or emit electric or
magnetic field energy, degrade or decompose under controlled conditions,
modify adhesion, soften or stiffen a material, etc.

[0066] Dyes, for examples, are known to those skilled in the art and can
readily be classified by chemical structure, e.g., azo dyes (strong and
cost-effective) and anthraquinone dyes (weak and expensive). The types of
dyes useful for this disclosure include those that are readily modified
to include the azide group or the non-activated acetylene group.

[0067] The compound comprising a functional entity and at least one
pendant non-activated acetylene group or azide group can be added to the
composition before cross-linking, for example when compounding the
substantially linear copolymer and the curing agent. Then during
cross-linking, the pendant azide group (or non-activated acetylene group)
of the compound comprising the functional entity would react with the
non-activated acetylene group (or the azide group) of the substantially
linear copolymer as disclosed above to covalently bond the functional
entity into the polymer. For example, a compound with a functional entity
and a pendant azide group would react with the interpolymerized
non-activated acetylene cure-site monomer of the substantially linear
copolymer to covalently bond the functional entity to the substantially
linear copolymer through a triazole linkage. The same techniques could be
used to anchor a functional entity to a finished adhesive or coating, for
example in an image-wise fashion, to create patterns of different
properties (e.g., color).

[0068] In the embodiments described above, the amount of non-activated
acetylene to azide generally is in a ratio of 1:1 or higher. However, the
amount may be less than 1:1 so as long as there is a sufficient number of
azide-acetylene cross-links to achieve cross-linking It is acceptable to
leave some of the non-activated acetylene groups or some of the azide
groups unreacted if the desired mechanical properties can be achieved.

[0069] When employing the azide-acetylene cure systems described above, a
dispersing agent such as a hydrocarbon, ester (e.g., ethyl acetate),
ketone (e.g., methyl ethyl ketone), or other solvent in which both the
substantially linear copolymer and the curing agent are soluble, may be
necessary to ensure homogeneous dispersion of the curing agent in the
substantially linear copolymer.

[0070] Additional monomers also may be included, such as described below,
to provide particular properties. For example, acid-functionalized
monomers or polar monomers.

[0071] The acid functional monomer, where the acid functional group may be
an acid per se, may include carboxylic acid, or a portion may be a salt
thereof, such as an alkali metal carboxylate. Useful acid functional
monomers include, but are not limited to, those selected from
ethylenically unsaturated carboxylic acids, ethylenically unsaturated
sulfonic acids, ethylenically unsaturated phosphonic acids, and
combinations thereof. Examples of such compounds include those selected
from acrylic acid, methacrylic acid, itaconic acid, fumaric acid,
crotonic acid, citraconic acid, maleic acid, oleic acid,
β-carboxyethyl(meth)acrylate, 2-sulfoethyl methacrylate, styrene
sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, vinylphosphonic
acid, and combinations thereof.

[0072] Due to their availability, acid functional monomers of the acid
functional copolymer are generally selected from ethylenically
unsaturated carboxylic acids, i.e. (meth)acrylic acids. When even
stronger acids are desired, acidic monomers include the ethylenically
unsaturated sulfonic acids and ethylenically unsaturated phosphonic
acids. The acid functional monomer is generally used in amounts of 1 to
15 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts
by weight total monomer.

[0073] Polar comonomers may also be included to impart useful properties
in the substantially linear copolymer, such as resistance to oils,
adherence to low surface energy substrates, and the like.

[0074] Examples of useful polar copolymerizable monomers include, but are
not limited to those selected from the group consisting of acrylic acid,
methacrylic acid, itaconic acid, hydroxyalkyl acrylates, styrene sulfonic
acid and its sodium salt, maleic acid, fumaric acid, citraconic acid,
acrylamides, substituted acrylamides, N-vinyl lactams such as
N-vinylpyrrolidone, N-vinylcaprolactam, acrylonitrile, dimethylamino
ethylmethacrylate, and combinations thereof. Polar copolymerizable
monomers include those selected from the group consisting of acrylic
acid, methacrylic acid, acrylamides, substituted acrylamides, and
combinations thereof, for reasons of availability and influence on
polymer properties.

[0075] Representative examples of suitable polar monomers include, but are
not limited to 2-hydroxyethyl(meth)acrylate; N-vinylpyrrolidone;
N-vinylcaprolactam; acrylamide; mono- or di-N-alkyl substituted
acrylamide; t-butyl acrylamide; dimethylaminoethyl acrylamide; N-octyl
acrylamide; poly(alkoxyalkyl)(meth)acrylates including
2-(2-ethoxyethoxy)ethyl(meth)acrylate, 2-ethoxyethyl(meth)acrylate,
2-methoxyethoxyethyl(meth)acrylate, 2-methoxyethyl methacrylate,
polyethylene glycol mono(meth)acrylates; alkyl vinyl ethers, including
vinyl methyl ether; and combinations thereof. Preferred polar monomers
include those selected from the group consisting of
2-hydroxyethyl(meth)acrylate and N-vinylpyrrolidinone. The polar monomer
may be present in amounts of 0 to 10 parts by weight, preferably 1 to 5
parts by weight, based on 100 parts by weight total monomer.

[0076] When used, vinyl monomers useful in the substantially linear
copolymer include but are not limited to: vinyl esters (e.g., vinyl
acetate, vinyl propionate, and vinyl butyrate), styrene, substituted
styrene (e.g., α-methyl styrene), vinyl halide, and combinations
thereof. A preferred monomer with a high Tg (glass transition
temperature) is vinyl acetate for reasons of availability. Such vinyl
monomers are generally used at 0 to 5 parts by weight, preferably 1 to 5
parts by weight, based on 100 parts by weight total monomer.

[0077] When employing the azide-acetylene cure systems described above,
other curing agents, such as azirdine amide, may be added to the
substantially linear copolymer for cross-linking. However, care must be
taken to select the additional curing agents so that they do not react
with the azide groups or non-activated acetylene groups prior to the
azide-non-activated acetylene cure. For example, when using substantially
linear copolymers comprising interpolymerized azide cure-site monomers,
some of the additional curing agents mentioned below will react with the
azide group before the azide-acetylene cure. In the case of a
substantially linear copolymer comprising interpolymerized azide
cure-site monomers, some of the additional curing agents mentioned below
would have to be used either before the azide is introduced or after the
azide is reacted with the non-activated acetylene group. Examples of
additional curing agents include, but are not limited to those selected
from the group consisting of multifunctional acrylates such as
diacrylates, triacrylates, and tetraacrylates, such as
1,6-hexanedioldiacrylate, poly(ethylene glycol)diacrylates,
poly(butadiene)diacrylates, polyurethane diacrylates, and
trimethylolpropane triacrylate; 4-acryloxybenzophenone; divinyl benzene;
and combinations thereof. Preferred cross-linkers are those selected from
the group consisting of 1,6-hexanedioldiacrylate (HDDA), poly(ethylene
glycol)diacrylates, 4-acryloxybenzophenone, and combinations thereof for
reasons of availability.

[0078] Additional curing agents also may be added to control the polymeric
architecture allowing more freedom in attaining a specific desired
performance. Additional curing agents, if included, are typically added
in a range of about 0.01 to about 0.5 percent by weight, preferably about
0.02 to about 0.1 percent by weight, most preferably about 0.03 to about
0.08 percent by weight, based upon the total weight of monomer included.

[0079] The compositions can include any of the adjuvants commonly employed
in curable polymer formulations. An organic or inorganic filler may be
added to the composition to improve physical properties, such as tensile
strength, density, and modulus. Fillers include: carbon black; silica; or
other mineral fillers such as hydrotalcite, or barium sulfate, and
combinations thereof.

[0081] Other optional additives include, for example, stabilizers (e.g.,
antioxidants or UV-stabilizers), pigments (e.g., dyes), flame retardants,
medicaments, and the like. The use of such additives is well known to
those of ordinary skill in the art.

[0082] Fibers, glass bubbles, and retro-reflective beads may also be
added. Fibers can be of several types, generally polymeric or glass. The
former can be nylon, polyester, polyamide, epoxy and the like. Glass
fibers fall into two types E- and S-glass. E-glass has good insulation
properties and maintains its properties up to 1500° F.
(815° C.). S-glass has a high tensile strength and is stiffer than
E-glass. The fiber type is chosen for its compatibility with the
substantially linear copolymer and to provide enhanced properties such as
tensile and elongation. Glass bubbles are generally used to lower
density, add topology to the substantially linear copolymer coatings or
films, reduce cost, and/or to control contact area. A series of glass
microbubbles with variation in size and crush strength is available from
3M Co., St. Paul, Minn. In pressure sensitive adhesives, glass bubbles
offer the ability to control the initial adhesion by reducing contact
until the bubbles are crushed by force and allowing full contact of the
adhesive layer.

[0083] The curable composition can typically be prepared by mixing one or
more substantially linear copolymer(s), the curing agent (if needed), any
additional curatives (if desired), and any adjuvants (if desired) in
conventional processing equipment. This may be done in a solvent or in a
solvent-less environment. The desired amounts of compounding ingredients
and other conventional adjuvants or ingredients can be added to the
curable composition and intimately admixed or compounded therewith by
employing any of the conventional mixing devices such as extruders,
static mixers, internal mixers, (e.g., Banbury mixers), two roll mills,
or any other convenient mixing devices. The temperature of the mixture
during the mixing process typically is kept safely below the
cross-linking temperature of the composition. Thus, the temperature
typically should not rise above about 60° C., about 80° C.,
or even about 100° C. During mixing, it generally is desirable to
distribute the components and adjuvants uniformly.

[0084] In one embodiment of this disclosure, the compounded composition
may be processed (such as by coating or molding) in a solvent or a
solvent-less environment. For example, the azide-containing compound
(e.g., the substantially linear copolymer comprising interpolymerized
azide cure-sites) and the non-activated acetylene-containing compound
(e.g., the curing agent) may be coated without the presence of a solvent,
or may be coated in the presence of a solvent. The solvent may be
removed, for example, by thermal evaporation. Additionally, the amount of
solvent in the compounded composition may be adjusted, depending on the
application so as to obtain a desired viscosity of the composition. For
example, in pressure sensitive adhesive applications, the viscosity may
be adjusted to obtain a desired flow rate for the process.

[0085] In one embodiment of this disclosure, the compositions may be
compounded and/or processed (such as by coating or molding) in the
presence of water. Because the reaction of the azide group and the
non-activated acetylene group is not sensitive to water, there may be no
need to take special precautions to prevent moisture from being present.
For example, there may be no need to dry fillers or other reactants, or
control the humidity of the reaction atmosphere. Because of the water
insensitivity, the substantially linear copolymers may be made in latex
form and processed without the use of organic solvents, which may be
environmentally advantageous.

[0086] The compounded compositions of this disclosure may be cross-linked
via thermal activation. Thus, when the heat is removed, the composition
does not further cure. Temperatures for cross-linking include those above
100° C. or even above 140° C. In some embodiments, a metal
catalyst may not be used in the reaction of the azide with the
non-activated acetylene. In some embodiments, a metal catalyst may be
used to catalyze the azide-non-activated acetylene reaction. Examples of
such metals catalysts include metal and metal salts such as those
including: copper, nickel, palladium, and platinum.

[0087] In one embodiment, the compositions of this disclosure may be
applied in adhesive or coating applications, or used as structural
polymers, such as fiber reinforced composites, filled polymers, etc.

[0088] In coating applications, for example, a layer of the substantially
linear copolymer comprising the azide-acetylene cure system is applied to
a substrate to provide or modify the substrate's features such as color,
adhesion, surface finish, surface energy, scratch resistance, abrasion
resistance, chemical resistance, weatherability, and so forth.

[0089] In filled polymers, for example, a discontinuous material (e.g.,
filler) is incorporated into the matrix (e.g., the substantially linear
copolymer comprising the azide-acetylene cure system) to provide
features, advantages, and benefits above and beyond those available from
each of the separate components. In reinforced composites, for example,
fillers are added to the substantially linear copolymer comprising the
azide-acetylene cure system to improve the mechanical properties of the
substantially linear copolymer comprising the azide-acetylene cure
system. In a structural article, a shaped piece of material, is added to
the article to provide dimensional control of the article. A structural
article may also be a unitary (non-assembled) item such as an
injection-molded object like a comb, a hand-held magnifier, a concrete
stop for a parking space, etc.

[0090] In one embodiment of this disclosure, the composition is used as an
adhesive in, for example, a PSA (pressure sensitive adhesive).

[0091] The compositions prepared in accordance with the present disclosure
are easily coated upon suitable flexible or inflexible backing materials
by conventional coating techniques to produce adhesive coated sheet
materials in accord with the present disclosure. The flexible backing
material may be any material conventionally utilized as a tape backing or
any other flexible material. Typical examples of flexible backing
materials employed as conventional tape backings, which may be useful for
the adhesive compositions of the present disclosure include those made of
paper, plastic films such as polypropylene, polyurethane, polyethylene,
polyvinyl chloride, polyester (e.g., polyethylene terephthalate),
cellulose acetate, and ethyl cellulose.

[0092] Backings may also be prepared of fabric such as woven fabric formed
of threads of synthetic or natural materials such as cotton, nylon,
rayon, glass, ceramic material, and the like or nonwoven fabric such as
air laid webs of natural or synthetic fibers or blends of these. The
backing may also be formed of metal, metalized polymeric films, or
ceramic sheet materials. The coated sheet materials may take the form of
any article conventionally known to be utilized with PSA compositions
such as labels, tapes, signs, covers, marking indicia, and the like.

[0093] These coated papers or thermoplastic films are often siliconized or
otherwise treated to impart improved release characteristics. One or both
sides of the backings or liners could have such release characteristics.
Generally the backing or substrate material is about 50 μm
(micrometer) to about 155 μm in thickness, although thicker and
thinner backing or substrate materials are not precluded.

[0094] The PSA compositions of the present invention may be coated by any
of a variety of conventional coating techniques known in the art, such as
roll coating, spray coating, knife coating, extrusion, die-coating, and
the like.

[0095] An advantage of using the composition of this disclosure is that a
solvent-less adhesive or coating may be generated. Further, the cohesive
strength, tensile, modulus, and adhesion performance of the adhesive also
may be improved.

EXAMPLES

[0096] Advantages and embodiments of this disclosure are further
illustrated by the following examples, but the particular materials and
amounts thereof recited in these examples, as well as other conditions
and details, should not be construed to unduly limit this invention. In
these examples, all percentages, proportions and ratios are by weight
unless otherwise indicated.

[0097] All materials are commercially available, for example from
Sigma-Aldrich Corporation, St. Louis, Mo., or known to those skilled in
the art unless otherwise stated or apparent.

[0099] Using a stress-strain controlled rheometer, AR2000, (TA
Instruments, New Castle, Del.) samples were placed between two 20 mm
parallel plates. The bottom plate was heated to 160° C. and held
at that temperature for the duration of the experiment. The top plate was
oscillated with a frequency of 1 Hertz and strain of 1% of 2 mm to
generate the elastic modulus of the test sample. Readings were taken
every 30 s and recorded by a motor transducer attached to the top plate.
Data was then stored as elastic modulus (G') in Pascals (Pa) vs. time in
seconds (s) and plotted as G' versus time or log G' versus time.

Preparation of Reagents

[0100] CH3CH2C(OCH2CH--OHCH2N3)3 was
prepared as follows: Step
1--CH3CH2C(CH2OCH2CHOHCH2Cl3)3 was
prepared by melting a mixture of trimethylolpropane (134 g) and 1 g of
C6H5CH(SO2CF3)2 (made by reacting benzyl
magnesium chloride with triflyl fluoride according to Journal of Organic
Chemistry, 38, p. 3358, 1973) in a flask equipped with stirring bar and
dropping funnel. The temperature was controlled at 70° C. while
epichlorohydrin (277 g) was added over a period of two hours. Step
2--This tri-chloro compound (without purification) was converted to the
tris-azide by adding it over a period of one hour to a hot solution
(100° C.) of sodium azide (200 g) and sodium hydroxide (5 g) in
water (500 g). The mixture was stirred for 10 hours at 100° C.,
then allowed to cool. The aqueous phase was separated from the product
phase and extracted with ethyl acetate (500 g). The ethyl acetate phase
was combined with the product phase and residual water was removed by
azeotropic distillation. The dried product solution in ethyl acetate was
filtered. The ethyl acetate was removed on a rotary evaporator with a
water-aspirator vacuum and temperature bath. The product was a viscous
yellow liquid. Structural confirmation was achieved by FT-IR
spectroscopy.

[0101] PEG 1000 diazide was prepared as follows: 1000-Molecular weight
polyethylene glycol (100 g) was melted at 60° C., stirred, and
purged with nitrogen. Thionyl chloride (50 g) was added gradually
allowing hydrogen chloride and sulfur dioxide to evolve. After obvious
gas evolution was complete, the mixture was heated for an additional 16
hours until the hydroxyl peak in the infrared spectrum was eliminated.
Excess thionyl chloride was removed by sparging with nitrogen until the
effluent gas no longer created a white smoke with the fumes from a bottle
of ammonium hydroxide. The resulting residue (20.4 g) was mixed with a
solution of sodium azide (4 g) in water (120 g). This mixture was heated
at 100° C. for 24 hours, then cooled and extracted twice with 100
mL toluene. Stripping the combined toluene phases left 15.0 g of
poly(ethylene glycol)diazide, characterized by an infrared absorption for
the azido group at 2103 cm-1.

[0102] N3CH2CH2OCH2CH(OH)CH2N3 was prepared
as follows: Step 1: 2-chloroethanol (1208 g), was mixed with SnCl4
(11.6 g, 5.2 mL) in a 5 L, 3-necked flask and heated to 70° C.
Epichlorohydrin (1112 g) was added over four hours at a rate to maintain
the temperature in the range of 60° C.-75° C. After
addition was complete, the reaction mixture was held at 70° C. for
one hour, then was cooled to 30° C. and methylene chloride (1000
g) was added. A pre-dissolved mixture of ethylenediamine tetraacetic acid
disodium salt (48 g), sodium hydroxide (9.2 g), and water (1000 g) was
added and stirred for one hour, then allowed to separate. The lower
(organic) phase was extracted with 1000 mL of water. The organic phase
was distilled at atmospheric pressure to remove CH2Cl2. The
product was distilled between 116° C. and 130° C. at 7 mm
Hg, providing 1050 g of the desired adduct. Step 2: The product from Step
1 (200 g) was mixed with dimethyl sulfoxide (200 g) and water (14 g) in a
2 L, 3-neck flask and heated towards 90° C. Sodium azide (200 g)
was added gradually beginning at 50° C. and continued as heating
proceeded to 90° C. The addition took 30 min and the temperature
was at 90° C. when addition was complete. The reaction was allowed
to run for 7.5 hrs. Water (1000 mL) was added and the mixture was stirred
for 15 min then transferred to a reparatory funnel. It was convenient to
let this mixture sit overnight before separating. Methylene chloride (200
g) was added to the product phase and then 200 mL deionized water. The
phases then were separated. The organic phase was stirred for 30 min with
20 g anhydrous NaSO4 then filtered into a 1000 mL 3-neck flask. The
product was stripped using a water bath at 55° C., an aspirator,
and a nitrogen purge for about 2 hours to yield 160 g of the desired
di-azidoalcohol. Structural confirmation was achieved by FT-IR
spectroscopy.

[0103] N3CH2CH2O[CH2CH(CH2N3)O]6CH3 was prepared as follows: The alcohol
N3CH2CH2O[CH2CH(CH2N3)O]6H was
prepared by the procedure used for
N3CH2CH2OCH2CH(OH)CH2N3 (above) except that
the mole ratio of epichlorohydrin to 2-chloroethanol was 6:1 in Step 1,
the non-volatile product was used in Step 2 without distillation, and
xylene was used instead of methylene chloride to dilute the azide
compound before washing in Step 2. Structural confirmation was achieved
by FT-IR spectroscopy. In a final step, the alcohol was converted to its
methyl ether,
N3CH2CH2O[CH2CH(CH2N3)O]6CH3, by
mixing the alcohol (69.5 g) with dimethyl sulfate (25.2 g) then slowly
adding 50% aqueous sodium hydroxide solution (25.6) over a period of 35
min with vigorous agitation while keeping the batch temperature near
30° C. using a cooling water bath. Excess dimethyl sulfate then
was consumed by adding ammonium hydroxide (6.5 g) and stirring for an
additional hour. The product was isolated by adding xylene (250 mL) to
the mixture, and extracting three times with water (100 mL). The organic
phase was stripped under vacuum (20 mm Hg and 80° C. bath
temperature) to yield 65 g of product. Structure confirmation was by
FT-IR spectroscopy.

[0104] N3CH2CH2OH (2-azidoethanol) was prepared by adding
2-chloroethanol (80.5 g, 1 mol) dropwise over 30 min to a 70° C.
stirred solution of sodium azide (66.95 g, 1.03 mol, American Azide
Corp., Las Vegas, Nev.) in deionized water with 1% wt sodium hydroxide
(EMD, Gibbstown, N.J.). The reaction then was heated at 100° C.
for 5 hrs. 2-Azidoethanol was extracted from the reaction mixture with
toluene (EMD, Gibbstown, N.J.) and dried via azeotropic distillation of
toluene and water. The dried solution was filtered, then toluene was
removed on a rotary evaporator with water-aspirator vacuum and water-bath
heating. Structural confirmation was achieved by FT-NMR and FT-IR
spectroscopy. Yield was approximately 75%.

[0105] The poly-urethane of N3CH2CH2OH with polyisocyanate
sold under the trade designation "DESMODUR" N3200 (Bayer MaterialScience
LLC, Pittsburgh, Pa.) was prepared as follows. DESMODUR N3200 (9.56 g)
was dissolved in toluene (50 g) and 2-azidoethanol (5.74 g) was added.
Dibutyltin dilaurate (0.03 g) was added and the solution was heated at
85° C. for 1 hr. The solvent was removed on a rotary evaporator
with a water-aspirator vacuum and water-bath heating. The structure was
confirmed by FT-IR spectroscopy.

[0106] The tris-2-azido-ethyl trimesoate was prepared as follows:
trimesoyl trichloride (26.6 g) was dissolved in toluene (400 mL) and
azidoethanol (29.1 g) was added. Triethyl amine (30.3 g) was added
gradually with stirring, keeping the temperature below 60° C.
After stirring the mixture for an additional hour, it was washed four
times with 100 mL water and filtered. The solvent was removed on a rotary
evaporator with a water-aspirator vacuum and water-bath heating. The
tris-2-azido-ethyl trimesoate was obtained as a liquid (45.2 g) that
crystallized very slowly. The structure was confirmed by FT-IR

[0107] Hexane-1,6-bis-azidoethyl-urethane was prepared as follows:
hexamethylene diisocyanate (14 g) was dissolved in toluene (60 g) and
2-azidoethanol (16 g) was added. Dibutyltin dilaurate (0.015 g) was added
and heated to 85° C. An exothermic reaction occurred and then the
solution was allowed to cool. The solvent was removed on a rotary
evaporator with a water-aspirator vacuum and water-bath heating. The
structure was confirmed by FT-IR spectroscopy.

[0108] The 2,3-dicarboxy-1,4-diaminoanthraquinone-N-hydroxyethylimide was
prepared as follows: Sulfuric acid (630 g) was placed in a 1 L 3-neck
flask and was heated to 80° C. Because of the exothermic reaction
the 1,4-diamino-2,3-anthroquinone dicarbonitrile (123.44 g, Aceto Corp.
Lake Success, N.Y.) was added slowly. A water bath was used to maintain a
reaction temperature of 140° C.-150° C. After completing
the addition of the 1,4-diamino-2,3-anthroquinone dicarbonitrile, the
reaction was held at around 150° C. for 1 hour. The reaction was
then cooled to 40° C. Water (255.04 g) then was added to the flask
and the mixture was cooled to room temperature. The mixture was filtered
very slowly through a glass frit funnel and washed with water. The
filtrite (residue) was crushed and air dried. The product yield was 175
g.

[0109] The hydroxyl form of
2,3-dicarboxy-1,4-diaminoanthraquinone-N-hydroxyethylimide was prepared
as follows: 60 g of the blue dye intermediate
(2,3-dicarboxy-1,4-diaminoanthraquinone-N-hydroxyethylimide, above) was
mixed with 1,2-dichlorobenzene (320.42 g) and ethanolamine (26.629 g).
The mixture was heated to 120° C. Some of the solvent (with a
small amount of water) was distilled out of the mixture through a
dean-stark trap. The temperature was gradually raised to 150° C.
and held for three hours. The mixture was cooled to room temperature and
methanol (500 mL) was stirred-in. The mixture was then filtered. The
filtrite was mixed with 25 g concentrated hydrochloride in 500 g of
water, stirred well, filtered and repeated. The filtrite was then mixed
with 500 mL of methanol and stirred filtered. The filtrite was air dried.

[0110] An azido-dye compound was prepared as follows: The hydroxyl form of
the blue dye 2,3-dicarboxy-1,4-diaminoanthraquinone-N-hydroxyethylimide
(0.515 g) was mixed with excess thionyl chloride (20 mL) and refluxed
overnight, then the excess thionyl chloride was removed by sparging. The
solid residue was mixed with 1 g of sodium azide in 20 mL dimethyl
sulfoxide and heated for 16 hrs. The reaction mixture was diluted with
water (20 mL) and extracted three times with 100 mL of toluene, which
formed a blue organic solution as an upper phase each time. The solvent
was removed from the combined toluene extracts leaving a dark solid
residue whose infrared spectrum (nujol mull) showed a strong peak for
azide at 2102 cm-1.

[0111] Propargyl methacrylate--A two-phase mixture of methacryloyl
chloride (21 g), propargyl alcohol (11.2 g), and cyclohexane (100 mL) was
stirred in a 250 mL flask. Triethyl amine (21.2 g) was added slowly to
keep the mixture below reflux temperature, and a solid phase gradually
formed. The mixture was allowed to stir for 16 hours, then washed three
times with 100 mL of cold water to remove triethylammonium hydrochloride,
leaving a yellow solution. 5 g of activated carbon sold under the trade
designation "DARCO" (Norit Americas Inc., Marshall, Tex.) was stirred
into the solution for 2 hours and then was filtered off. The cyclohexane
was removed from the nearly-colorless solution via rotary evaporation
with aspirator vacuum and a pot temperature of 40° C., leaving 18
g of pale oil, whose identity was confirmed by FT-IR peaks at 3297, 2931,
1726, 1678, and 1638 cm-1.

[0112] 2-Azidoethyl methacrylate--A mixture of methacryloyl chloride (21
g), 2-azidoethanol (17.5 g) and cyclohexane (100 mL) was stirred in a
water-cooled jacketed flask and triethyl amine (21.2 g) was added
gradually keeping the temperature below 15° C. The mixture was
stirred two hours more and washed twice with 100 mL of water. The aqueous
phases were combined and extracted with 100 mL of cyclohexane. The
combined yellow cyclohexane phases were treated with DARCO (5 g) with
stirring, then filtered. The solvent was removed on a rotary evaporator
with water-aspirator vacuum and bath temperature of 35° C.,
leaving a non-volatile fraction of 18.15 g of very pale yellow monomer,
characterized by FT-IR spectroscopy. Peaks at 2931, 2103, 1723, 1678, and
1639 cm-1 support the proposed structure.

[0113] Non-activated acetylenic functional polymer A was prepared as
follows: isooctyl acrylate (3M Co., St. Paul, Minn.), propargyl acrylate
(GFS Chemicals Columbus, Ohio) and acrylic acid (Dow Chemical Midland,
Mich.) were added in a ratio of 94:5:1.45% by weight solids of the
mixture was added to ethyl acetate/isopropanol (70/30), 0.2%
2,2'-azobis(2-methylbutyronitrile) obtained under the trade designation
"VAZO 67" (DuPont, Wilmington, Del.). The vessel was purged with nitrogen
for 35 s at 1 L/min and then held for 24 hrs at 57° C.

[0114] Approximately 50 mg of the polymer solids was weighed and diluted
in 10 mL of tetrahydrofuran (inhibited with 250 ppm butylated
hydroxytoluene). The polymer solution was then run through a 0.45
micrometer syringe filter and analyzed by size exclusion chromatography.

[0116] Molecular weight values were determined by calibrating the system
against narrow dispersity molecular weight polystyrene standards (from
377, 400-580 Mp (peak molecular weight), Varian, Palo Alto, Calif.). The
acetylenic functional polymer sample was fitted using a 3rd order
polynomial fit to determine the molecular weight. For the non-activated
acetylenic functional polymer A, the weight average molar mass (Mw) was
2.831×105, the number average molar mass (Mn) was
6.347×104, the average molar mass (Mz) was
8.236×105, and the polydispersity (Mw/Mn) was 4.46.

[0117] Non-activated acetylenic functional polymer B was prepared as
follows: butyl methacrylate (Lucite International, Cordova, Tenn.),
methyl methacrylate (Arkema Inc., Philadelphia, Pa.) and propargyl
methacrylate (described above) were added in a ratio of 49:49:2.30% by
weight solids of the mixture was added to ethyl acetate/isopropanol
(99/1), and 0.2% VAZO 67. The vessel was purged with nitrogen for 35 s at
1 L/min and then held for 24 hrs at 57° C.

[0118] An azide functional polymer was prepared as follows: butyl
methacrylate (Lucite International, Cordova, Tenn.), methyl methacrylate
(Arkema Inc., Philadelphia, Pa.) and 2-azidoethyl methacrylate (described
above) were added in a ratio of 49:49:2. To a 30% by weight solids of the
mixture in ethyl acetate/isopropanol (99/1), 0.2% VAZO 67 was added. The
vessel was purged with nitrogen for 35 s at 1 L/min and then held for 24
hrs at 57° C.

[0119] A polymer comprising a non-activated acetylenic functional group
and an azide functional group was prepared as follows: butyl methacrylate
(Lucite International, Cordova, Tenn.), methyl methacrylate (Arkema Inc.,
Philadelphia, Pa.), 2-azidoethyl methacrylate, and propargyl methacrylate
were added in a ratio of 48:48:2:2. To 30% by weight solids of the
mixture in ethyl acetate/isopropanol (99/1), 0.2% VAZO 67 was added. The
vessel was purged with nitrogen for 35 s at 1 L/min and then held for 24
hrs at 57° C.

[0120] Trispropargyl trimesoate was made by dissolving trimesoyl
trichloride (26.6 g) in 200 mL of toluene, then adding propargyl alcohol
(17.2 g), and then adding 30.4 g of triethylamine in ten portions at a
rate to keep the reaction temperature below 60° C. An additional
300 mL of toluene was added to allow the slurry to be stirred. The
mixture was allowed to react for 4 more hours and then washed four times
with 100 mL water. The organic phase then was filtered through a paper
filter. The toluene was removed by rotary evaporation, leaving 31.7 g of
a viscous oil, which gradually solidified and was characterized by FT-IR
spectroscopy. Peaks at 3287, 2124, and 1732 cm-1 support the
proposed structure.

EXAMPLES

Example 1

[0121] To 1.10 g of the non-activated acetylenic functional polymer A,
0.01 g of CH3CH2C(OCH2CH(OH)CH2N3)3 was
added. The sample was mixed, coated on liner, and air dried at room
temperature for 24 hours.

[0123] To 2.2 g of non-activated acetylenic functional polymer A, 0.02 g
of N3CH2CH2O[CH2CH(CH2N3)O]6CH3
was added. The sample was mixed, coated on liner, and air dried at room
temperature for 24 hours.

Example 3

[0124] To 2.2 grams of non-activated acetylenic functional polymer A, 0.06
g of the PEG 1000 diazide was added. The sample was mixed, coated on
liner, and air dried at room temperature for 24 hours.

Example 4

[0125] To 2.2 g of non-activated acetylenic functional polymer A, 0.02 g
of N3CH2CH2OCH2CH(OH)CH2N3 was added. The
sample was mixed, coated on liner, and air dried at room temperature for
24 hours.

Example 5

[0126] To 2.2 grams of non-activated acetylenic functional polymer A, 0.02
g of the poly-urethane of N3CH2CH2OH with polyisocyanate
was added. The sample was mixed, coated on liner, and air dried at room
temperature for 24 hours.

Example 6

[0127] To 2.2 g of non-activated acetylenic functional polymer A, 0.02 g
of the tris-2-azido-ethyl trimesoate dissolved in 0.18 g of ethyl acetate
was added. The sample was mixed, coated on liner, and air dried at room
temperature for 24 hours.

Example 7

[0128] To 2.2 g of non-activated acetylenic functional polymer A, 0.02 g
of the hexane-1,6-bis-azidoethyl-urethane dissolved in 0.27 g ethyl
acetate was added. The sample was mixed, coated on liner, and air dried
at room temperature for 24 hours.

[0129] Comparative Example 1 and Examples 1-7 were removed from the liner,
loaded onto a rheometer probe and tested following the rheometer method
above. Shown in FIG. 1 is a graph of G' versus time for Comparative
Example 1 (Comp. Ex. 1) and Examples 1-3. Shown in FIG. 2 is a graph of
G' versus time for Comparative Example 1 and Examples 4-7. As shown in
FIGS. 1 and 2, the non-activated acetylenic functional polymer A
comprising an azide curing agent showed a marked increase in modulus with
time, indicating cross-linking

Example 8

[0130] To 3.3 g of the non-activated acetylenic functional polymer B, 0.02
g of N3CH2CH2O[CH2CH(CH2N3)O]6CH3
was added. The sample was mixed, coated on liner, and air dried at room
temperature for 24 hours.

[0132] To 1.6 g of the non-activated acetylenic functional polymer B, 1.6
g of the azide functional polymer was added. The sample was mixed, coated
on a liner, and air dried at room temperature for 24 hours.

Example 10

[0133] The dual functional polymer comprising a non-activated acetylenic
functional group and an azide functional group was coated onto a liner
and air dried at room temperature for 24 hours.

[0134] Examples 8, 9, and 10, and Comparative Example 2 were removed from
the liner, loaded onto the rheometer probe and tested following the
rheometer method above. Shown in FIG. 3 is a graph of log G' versus time
for Comparative Example 2 (Comp. Ex. 2) and Examples 8, 9, and 10.

Example 11

[0135] To 3.3 g of the azide functional polymer, 0.02 g of tris propargyl
trimesoate dissolved in 0.34 g ethyl acetate was added. The sample was
mixed, coated on liner, and air dried at room temperature for 24 hours.

[0137] To 3.3 g of the azide functional polymer, 0.01 g of tris propargyl
trimesoate dissolved in 0.34 g ethyl acetate was added. The sample was
mixed, coated on liner and air dried at room temperature for 24 hours.

[0138] Examples 11 and 12 and Comparative Example 3 were removed from the
liner, loaded onto the rheometer probe and tested following the rheometer
method above. Shown in FIG. 4 is a graph of log G' versus time for
Comparative Example 3 (Comp. Ex. 3) and Examples 11 and 12.

[0139] Example 13 was prepared as Example 1 except 0.02 grams of the
azido-dye compound was added to 2.2 g of non-activated acetylenic
functional polymer A. The sample was mixed, coated on liner, and air
dried at room temperature for 24 hours. The sample was then heated at
160° C. in an oven for 2 hrs. The polymer was then washed with
ethanol. The ethanol wash remained clear (i.e., the dye did not wash out
of the polymer), indicating the dye was reacted into the polymer.

[0140] Foreseeable modifications and alterations of this invention will be
apparent to those skilled in the art without departing from the scope and
spirit of this invention. This invention should not be restricted to the
embodiments that are set forth in this application for illustrative
purposes.

Patent applications by 3M Innovative Properties Company

Patent applications in class From nitrogen-containing monomer other than acrylonitrile or methacrylonitrile

Patent applications in all subclasses From nitrogen-containing monomer other than acrylonitrile or methacrylonitrile